It does NOT work when the drive is not marked as removeable like an usb HD. It is possible to remove the check, but then you should really know what you do. It is possible to do just a normal install onto an usb hd. Without installed binary 3d drivers you can boot it on other systems too. If you really want to ignore the removeable status check put a # in front of "exit 4". But be warned: now you can wipe out internal hds too...